1. Field of the Invention
The present invention relates to the field of data storage systems such as disk drives. The invention particularly relates to a slider design for use in an optical or magneto-optical read-write head for high density recording and reading of information onto and from a storage medium.
2. Description of the Related Art
Data storage systems such as those used with computer systems, typically store data magnetically or magneto-optically onto a storage medium. The data stored on the medium, whether magnetic or optical, is contained in spiral or concentric tracks. An optical data storage system described in U.S. Pat. No. 4,799,210 to Wilson, includes a laser diode assembly mounted on a fixed platform, and an optical head mounted on a movable stage. The laser beam is coupled to the movable head through a flexible optical fiber. Japanese patent application No. 59-117,180 describes another optical system mounted on the top or upper side of a slider.
Efforts to reduce the size and weight of optical heads are represented by optical integrated circuits or thin film structures. U.S. Pat. No. 4,911,512 to Yamamoto et al. describes a far-field type optical transducer, and a semi-conductor laser secured on a submount of silicon. A thin film silicon dioxide, SiO.sub.2, waveguide element and a glass waveguide layer are also fixed on the submount. A collimator lens, a beam splitter, and a focusing grating are formed on the glass waveguide layer.
Another attempt to achieve compactness and weight reduction of a magneto-optical head is described in U.S. Pat. No. 5,199,090 to Bell. The Bell patent describes a magneto-optic head fabricated on a glass slider and flown adjacent a magneto-optical disk. A transducer is fabricated on an end of the glass slider. A planar or channel waveguide structure, fabricated by ion exchange in the end face of the glass slider, couples light from a light source, such as a laser diode, to the disk for reading or writing.
Conventional magnetic read-write heads commonly utilize sliders as carriers for the magnetic assembly. These sliders are typically designed in compliance with the International Disk Drive Equipment and Material Association (IDEA) specifications. The following Table I illustrates conventional slider design characteristics that are not applicable yet to optical or magneto-optical sliders.
TABLE I SLIDER DESIGN - IDEA SPECIFICATIONS Mini Slider Micro Slider Nano Slider Pico Slider Length 0.160 inch 0.112 inch 0.080 inch 0.049 inch (4064 .mu.m) (2845 .mu.m) (2032 .mu.m) (1245 .mu.m) Width 0.125 inch 0.088 inch 0.063 inch 0.039 inch (3175 .mu.m) (2235 .mu.m) (1600 .mu.m) (991 .mu.m) Height 0.035 inch 0.024 inch 0.017 inch 0.012 inch (889 .mu.m) (610 .mu.m) (432 .mu.m) (305 .mu.m)
Optical heads present several slider design concerns. A first concern relates to the optical path of the optical assembly mounted on the slider. The optical path limits the ability to reduce the slider height, particularly if such a height forms part of the optical path. Another concern relates to the footprint (i.e., the projected surface area) of the slider, which should be sufficiently large to carry the optical assembly and the fibers mounted onto the slider, without affecting the aerodynamic flying performance of the optical head. Yet another consideration is the weight of the slider in light of the additional weight of the optical assembly and fibers.
Another design concern is the overall weight of the optical head. It is a desirable objective to reduce the slider weight in order to improve the data access time. However, the slider design in an optical or magneto-optical read-write head is more involved than the slider design of a magnetic head, since additional features are needed to accommodate the slider optical components such as a lens, a mirror, optical fibers, and a field generating magnetic coil in the case to a magneto-optical recording head. These additional components augment the fabrication complexity of the slider design, and further increase the access time.
For example, the pico slider might not be an effective aerodynamic platform because it is too small and light, causing the optical fiber stiffness to dominate the slider air bearing stiffness. The pico, nano and micro sliders might not be effective optical platforms because they are too thin, and probably would not meet the optical requirements of the head. The mini slider would satisfy the optical requirements of the head; however, the mini slider is too bulky and heavy, particularly with the added mass of the optical assembly.
The continuing trend toward miniaturization of data storage systems is faced with the foregoing and other concerns, and cannot be accomplished by an arbitrary reduction in size and weight of the sliders.